Steam generator



Dec. 9, 1930. y w R woon 1,784,407

STEAM GENERATOR 'Filed Aug.' 5. 1927 w I I J INVENTOR I ATTORNEYS'Patented Dec. 9, 1930 UNITED STATES PATENT OFFICE WILFRED It. WOOD, OFLONDON, ENGLAND, ASSIGNOR T0 INTERNATIONAL COMBUSTION ENGINEERINGCORPORATION, OF NEW YORK, N. Y., A CORPORATION OF DELAWARE STEAMGENERATOR f Application led August 5, 1927, Serial No.210,787, and inGreat Britain' February 14, 1927.

This invention relate-s to steam generators of the type in which theboiler is furnace shaped, i. e., it is its own furnace whereby theevaporating surfaces are subject to ra- 5 diant heat and very highcapacities are obtainable with relatively small installations.

One of the primary objects of my invention is to introduce fuel` and airintosuch a furnace in an effective manner.

Another object of my invention is to ensure elfective circulationthroughout such a boiler. K

A further object is to reduce the losses in combustibles in such aninstallation to a neg- Fig. 2 is a fragmentary section takensubstantially on the lin'e 2-2 of Fig. 1, a portion of the view beingbroken out to condense the figure,

Fig. 3 is a fragmentary plan view of a detail of the invention, and

Fig. 4 is a diagrammatic plan View illustrating the manner ofintroducing fuel to the furnace.

seen that my improved steam generator comprises, in general, acombustion chamber A; a boiler unit B arranged at the rear of thecombustion chamber and comprising an upper steam and water drum 4, alower water drum 5, and a bank of upright tubes 6 connecting said drums;and burner means C to be hereinafter fully described.

The combustion chamber A comprises side tubular water walls 7 (only oneof which appears in the drawings), a front tubular water wall 8, a reartubular water wall 9 composed of the first row of tubes of the bank oftubes 6, a top or roof tubular water wall 10 and tubes 11 marginal ofthe bottom of the ligible quantity; and also to burn coarser fuelReferring now to the drawings, it will be.

combustion space. Suitable sheathing is provided for enclosingv theside, front and top water walls.

The side walls 7 comprise a plurality of closely spaced' upright tubes,preferably finned, connected at their upper ends into headers 12 and attheir lower ends into headers 18. The upper headers 12 are preferablyconnected to the upper drum 4 of the boiler unit B by means of aplurality of bent tubes 14 andthe lower headers 13 mayl be directlyconnected into the lower drum 5 of the boiler unit as shown inl Fig. 1at 13a. The front wall 8 comprises a plurality of similarly finneduprightv tubes, each tube of which is connected at its upper end into aseparate header or junction box 15 and at its lower end into a separateheader or junction box 16. Each of t-he upper headers 15 has connectedthereinto a pair of tubes of the double row of tubes of which the roofwall 10 is composed, and these tubes are connected at their other endsinto the upper steam and water drum 4. It is to be noted-that I havepreferably provided the upper row of tubes of this double row with fins.Each of the lower headers 16 has connected thereinto a tube of thedouble row of tubes which constitute the tubes 11 marginal of the bottomof the combustion space. It will be seen that the headers 16 althoughclosely spaced transversely considered, are spaced suiciently apartvertically considered as to provide ample space between the tubes 11 sothat gravitating particles may pass therebetween to the refuse hoppers17. The tubes 11 are connected at their ends opposite the headers 16into the lower drum 5 of the boiler unit C.

From the foregoing it will be seen that .two upcomer tubes which connectinto the upper steam and water drums of the boiler Yunit B. Thuseffective circulation is ensured which is an important conslderation 1nboilers fired in the manner hereinafter appearing.

Pulverized fuel with carrying air is introduced into the combustionchamber A at the ,lower part thereof by means of the burners circlehaving its center in the axial line of the chamber ask diagrammaticallyindicated in Fig. 4. Air, in addition to that introduced at the burnerswith the fuel, is introduced into the combustion chamber by means of theair nozzles 18 located below the fuel burners, which air nozzles arearranged in like manner to the burners to tangentially deliver I theirair streams. The air admitted through these burners is preheated as bymeans of an air heater 19 located in the flue 20, which air heater isprovided with an air inlet 21 and an air outlet 22. The air may becaused to pass through the heater in any suitable manner as, forexample, by the draught of the flue, or by means of a fan (not shown) orboth. A duct 23, preferably branched and extending alongeach side of thecombustion chamber, leads the preheated air from the air heater outletto the nozzles 18.

From the foregoing it will be understood that the fuel streams injectedby the burners C in the manner described will be given a violentswirling motion. The air injected by the nozzles 18 is likewise given aviolent swirling motion. By so introducing the fuel and air a violentlyswirling vortical flame is produced, the axis of the vortex beingvertical, which flame sweeps and scours the tubes of the water wallshereinbeforementioned and produces a high rate of heat transmission. Byadmitting the air injected by the nozzles 18 in the lower part'of thecombustion chamber and below the point of fuel admission this air liftsthe flame whereby heavier fuel can be burned than has heretofore beenpossible, the' air lift holding the heavier particles up and ensuringtheir complete combustion. .The firing of the fuel in the lower part ofthe furnace chamber puts gravity and the draft to some extent inopposition, in consequence of which the time interval for combustion ofany given particle or particles is lengthened which not only makes itpossible to burn coarser fuel but also secures complete combustionwithin the combustion space, reducing the loss of combustibles to anegligible quantity.

Admission of air below the burners, in addition to its sustainingfeature, provides a body of air for the consumption of any of the fuelparticles which tend to sink below the level of fuel introduction.

In order to maintain the aforesaid swirling action throughout the hei htof the combustion chamber, I have provided additional air nozzles 24 inthe upper part of the combustion chamber which are also arrangedtangentially in like manner to the burners C. These nozzles larepreferably supplied with preheated combustion air under pressure.

Thus violent agitation, mixing and swirling of the fuel and flame streamis ensured in the upper portion of the combustion chamber.

The products of combustion leave the combustion chamber at the upperpart thereof and pass over the tubes of the boiler unit B. In thisconnection it is pointed out that the front row of tubes of the boilerunit are backed by a baffle 25 extending from the lower 'drum 5 to apoint short of the upper drum 4,

thus leaving sufficient space above the baiiie at.26 for the products ofcombustion to escape between the tubes of the front row 9. The productsof combustion then pass over the bank of tubes 6 to the outlet 27communicating with the liue 20. Although the temperature of the gasesentering the bank of tubes is high, the final exit temperature islowered by the bank of tubes, the superheater 28 which is located in theflue and by the air heater.

In order to ensure proper water delivery to the lower drum 5 of theboiler unit B, I have provided a baffle 29 for protecting the rear rowof tubes of the bank of tubes 6 from the direct heat of the gases ofcombustion.

I claiinz- 1. A boiler furnace comprising upright being connected withmore than one tube of.

the top wall, a lower water drum int which said bottom cross tubes areconnected, an upper steam and water drum into which the tubes of the topwater wall are connected, downiiow means connecting said drums and meansfor introducing pulverized fuel into said boiler furnace.

2. A boiler furnace comprising upright front, rear and side tubularwater walls, a top water wall composed of a plurality of rows of watertubes, a plurality of rows of cross tubes at the bottom, each tube ofsaid cross tubes being connected with a different tube of an uprightwall, and each tubeof said upright wall being connected with a dierentplurality of tubes of lsaid top wall, a water drum into which sailbottom cross tubes are connected, a steam drum into which the tubes ofthe top water wall are connected, an off-take for the products ofcombustion and means for introducing fuel to be burned in suspension.

3. A boiler furnace including upright front, rear and side tubular waterwalls, a

- top tubular water wall comprising a double rcw of tubes, cross tubesat the bottom, 4a header connecting each tube of said cross tubes with adifferent tube of one of the said upright walls, and a header connectingeachv of the last mentioned tubes with a different pair of tubes of saidtop wall.

4. A boiler furnace including upright front, rear and side tubular'waterwalls, a top tubular water wall comprising a double row of tubes, adouble row of cross tubes at the bottom, the tubes of one rowbeing-staggered with relation to the tubes of the other row, a headerconnecting each tube of said `cross tubes with a different tube of oneof v the said upright walls and a header .connectthata row of tubes ofsaid banktog'ether kwith a bale associated therewith constitute a rearsteam evaporating wallV of the combustion chamber subject to radiantheat substanT tially throughout its length, said 'baille terminatingshort of the top of the combustion chamber to provide an outlet for thegaseous products of combustion, other tubes of said bank being subjecttothe heat of the gaseous products leaving saidoutlet and still othertubes of said bank bein shieldedfrom the heat of the gaseous proiucts ofcombustion, the aforesaid front, side, top and bottom tubes and the rowof tubes constituting'the rear wall of the combustion chamber` beingconnected to -receive their water from the lower drum of the boilerunit.

6. In combination, a furnace-shaped boiler, meansfor introducin fueltangentially into the lower inart thereo to vbe burnedin space, andmeans for introducing air for combustion below the point offuelintroduction in n a manner to create an ascending vortical currentsweeping the Walls of the furnace-shaped boiler.

7. In combination, a furnace-shaped boiler,

lmeans for introducing fuel tangentially into the lower part thereof tobe burned in space, means for introducing air for'v combustion below thepoint of fuell introduction in a mannerA to createan ascending vorticalcurrent sweeping the walls of the furnace-shaped boiler, and means forintroducing air above the point of fuel introduction to maintain saidvertical current for the length of the fuel and flame stream.

8.V In combination, a furnace-shaped boiler, 'means for introducing fueltangentially intou the lower. part thereof to be `burned in space, meansfor tangentially introducing air for combustion below the point of fuelintroduction and means for tan entially introducing airabove the pointof el introduction.

9. In combination, va furnace having an unrestricted combustion chamberformed of upright steam evaporating surfaces, means for introducing fueltangentially into the lower part thereof to be burned in space, meansfor tangentially introducing air for combustion below the point of fuelintroduction and means for tangentially introducing air above the ointof fuel introduction.

10. In comination, a furnace having an unrestricted combustion chambervformed of upright steam evaporating surfaces, steam evaporatingsurfacesjextending across `the bottom, and steam evaporating surfacesextending across the top means for introducing fuel tangentially intothe lower part of said combustion chamber; means for tangentially meansfor tangentially introducing air abovev the point of fuel introductionand below said steam evaporating surfaces.

In testimony whereof I have hereunto signed my name. l

' WIIJFRED WOOD.

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